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WEL-COME. Construction of R.O.B. Sevashram, Udaipur. A Practical case study Presentation By P. R. Chandak Assistant Engineer, PWD Circle ,Udaipur (Raj.) Email:chandak.aha@gmail.com.
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Construction ofR.O.B. Sevashram, Udaipur A Practical case study Presentation By P. R. Chandak Assistant Engineer, PWD Circle ,Udaipur (Raj.) Email:chandak.aha@gmail.com
Construction of R.O.B Sevashram at Udaipur - one of the R.O.B. among 17 R.O.B in Six Cities of Rajasthan State was under taken by RUIDP as package No. UDA/BR/02 • Project funded by ADB loan No. 1674 IND. • There are 10 level crossings in Udaipur city .Among these 6 are manned, 3 are unmanned and one is closed. • There are 4 under bridges, for movement of traffic below railway track. • The Sevashram Rail-over bridge constructed on level crossing no. 77 B at Km 107/8-9 of Railway, to connect Udaipur city & Hiran Magri (a Satellite Town of Udaipur city).
Salient features of R.O.B. at Sevashram,Udaipur • Total length including approaches = 556.41 m • a Viaduct portion = 81.20 m • b Approach on Udaipur side = 151.18 m • c Approach On Hiran Magri side = 134.30 m • No. of Piers = 28 • No. Abutment = 4 • No. of Span • a) ‘Udaipur City’ Side = 3 No. 18 m each • b) ‘Hiran Magri Colony’ Side = 11 No. 18 m. each • c) Central Span over Railway Crossing = 1 No. 30 m • Foundation • i) P1 to P5 & P11 to P14 open with raft footing & concrete M-35 • ii) P6 to P10 Pile foundation due to revision • Decking Arrangement • i) Viaduct portion PSCI Girder 18 m Span with concrete M-45 & RCC slab of concrete M-40 • ii) Central Span over Railway is truss of high grade steel Fe-540 B confirming to IS 8500 with Composite Construction • Wearing Coat • Mastic on Viaduct & B.M+B.C on approaches • Approaches - Rein forced earth wall with GI Strips • Bearing - Elastomeric Bearing for viaduct portion • POT-PTFE Bearing for Central Span • Expansion joint - Strip seal Expansion joint
The Problem in construction and their solution for discussion are : I Foundation Problem – 1.Open foundation with raft footing as proposed by designer on the basis of five boreholes in a length of 281.20 m could not serve the purpose. 2. During excavation of foundation at beginning of work as per proposed level rock was not available in foundation for 12 piers out of 32 piers (P5 to P10) 3. Entire work front was blocked. The photograph shows Problem occurred during foundation work
*Due to traffic problem & looking to safety aspect further excavation of east side of Pier P6, P7 & P9 was asked not to dig more in depth as suitable foundation strata in nearby pits not available. To give relief to users east side of four lane was asked to complete first Real situation and facts are reported to project authority . Decided to call Expert for field visit to solve problem. After several discussion it was affirmed to go for Re-Geo-Technical investigation of each pier location. An appropriate agency was seArched so as not repeat the earlier mistake. Induced Problem Cost of re investigation Extra cost of const. Rate for Extra & Excess item Traffic movement problem/,public interest litigation. Media reports On the basis of Re-Geo-Technical investigation decided for pile foundation. In order to avoid change in design and cost at mid of work preliminary/initial stage, foundation should be ascertained by bore hole on each pier location . This experience was followed for Construction of R.O.B. At CRPF , Ajmer in one of the Project city. Visit Of Experts
2 Problem to improve approaches. The two approaches Udaipur side having a gradient of (-) 4.39 % in a length of 150 m & on HiranMagri side with 4.00% gradient in a length of 130 m. As a area known as HiranMagri it self tells that there must be rock. But on Udaipur side approach a height of 6.419 m was filled with soil on which Existing Ground was weak. The plate load test performed gives strength which is less to bear the load of embankment. Problem to improve ground. There were so many optional to improve ground bearing capacity. Discussion was done with experts about available options for finalizing one which one was cheaper, without involving much complicacy in execution and is of course fast. It was decided to lower down the existing level by 1.2 m below and refill the same depth with good quality material made by mixing river shingle & Quarry rubbish. This involve extra cost time in excavation & refilling additional quantity in ‘Udaipur City’ side approach. This also change scope of R.E. wall work in terms of height and quantity. All the design factor should be ascertained in advance to minimize delay/extra/excess.
3. Problems during pile boring • In pier P6 (E) & P7 (E) Pile Bogey was struck in the rock during process of pile boring for socket ting in rock. • The problem was refer to designer for technical advice and suggested. • Fill the pile under consolation by concrete of same grade as pile. • A new pile was proposed to be bored at another location looking to suitability of site Devra (a roadside idol/small-temple of god) and service road. • Revised the Pile cap from 7.5 x 4.9 x 1.5 to 10.5 x 4.9 x 1.5 for P6 (E) & 7.5 X 6.5 X 1.5 for P7 (E) with maintaining same speciation of Pile cap w.r.t. reinforcement and grade of concrete as per design. • Resulting extra cost, time and delay in work. • Induced problem – 1.)Regarding cost of boring, concrete and reinforcement of pile not considered, • 2) Problem of nearby utility shifting. • Alternative item/arrangement of bigger size pile During Boring driving in the D.P.R. It also helps in correcting tilt and shifts.
4 Problem While pouring concrete • In the P6 (W) actual quantity poured was substantially less than required and doubts in respect strength/quality. • Matter was discussed in PIU in consultation with DSC & PMC. • It is decided to reject pile under consideration. • New pile to be bored with revised the pile cap from 7.5 X 4.9 X 1.5 to 7.5 X 6.5 X 1.5 with maintaining earlier speciation of Pile cap with regard to reinforcement a grade of concrete as per design. • Resulting extra cost time and delay of work. • Pile cage should be lowered properly, Density of Bentonite during Pile Driving should be watched • Provision for suitable liner should be taken.
5.Problem Collapse of railwayembankment near track • Open foundation with raft was proposed for Pier P3 & P4 near Railway track • The highest unstable bank due to open foundation was 5.55 m near P3 (E) Close to Railway Track as per level sheet. • It was close to Railway track, bridge was skew to 350 During rainy season while train and fear of collapse is always. Due to heavy rain & vibration of train large portion of wet soil collapsed but little away from track. ROB was proposed keeping of provision 4 tracks (BG) • Bank was Restore to Original Position by sand bags, planks and bracing immediately. • Pile foundation should be preferred near Railway Track to avoid risks of collapse & railway accident Disasters where depth of excavation is more. Embankment Collapse
6.PROBLEM IN SUPPLY OF HIGH GRADE STEEL • The central span consist of standard truss made of high grade steel Fe 540B confirming to IS 8500. • The statical scheme is as • Main girder = Simply supported truss girder • Cross girder = Simply supported plate girder supported on the and longitudinal girder • Top cord bracing = lateral bracing in the form of Plate girder at every 5 m c/c • Deck level bracing = No bracing but the composite deck will provide lateral • stiffness • The details of steel quantity worked out as per B.O.Q are of different sizes. • The different structural member under statically scheme are consist of different sizes plates varying in thickness from 10 mm to 32mm. • C. Weight of size Individual plates ranges from 5MT to 35MT. • D. But it was brought in the notice of the department by the contractor that steel manufacturing company (SAIL) policy minimum order quantity specific size should not be less than 20 MT. • In order to facilitate, D.S.C.(Design, Supervision, Consultant) changed design of central span, as per the order policy of SAIL. • In revised design sizes of plates are of sizes10,12,16& 20 mm in thickness • The revised design had to be checked by proof checker & Railway authority. Due to revision quantity of steel was increased by15.23 Percent. • The Induced Problems are • Change in no. ,sizes of fasteners and holes. • Increase in sizes of gusset plates, wastes & cost of welding. • Policy of Industry should also be incorporated while designing.
Problem of Submerged Arc Welding • The steel frame so Proposed by D.S.C. though Project Authority to Railway for approval. Railway put a remark on drawings that members of steel frame should be welded by Submerged Arc Welding. • Actually this type of welding is special in nature as root weld by mig welding on a track where welding equipment move & member remain stationary. • Need a complete workshop fully equipped with skilled Manpower & different Machines, such arrangement is not available everywhere. • This entire fabrication work was got done by a Specialist firm in Vishvkarma Industrial Area Jhotwara Jaipur. • All the members of steel frame manufactured, assembled checked by third party & disassembled. • Transported to the site in pieces of main girder, cross girder ,top chord bracing & deck level for a complete set of two lane( half portion) • . Same activity is repeated for another half portion due to limitation of work shop area. • In B.O.Q. & Drawings Submerged Arc welding is neither included nor exist even in basic schedule of rates. • There is Extra cost involved in fabrication work • Basis of units for extra cost in fabrication are quantum of work in terms of MT or length of welding. • For this extra payment claimed by agency was decided in meeting of VAC (Variation Approval Committee) during Amicable Settlement. • In future special item should be proposed in B.O.Q.in consultation with line agency to avoid claims and litigation. • The above situation was kept in mind while construction of steel framed bridge work over canal in Kota, one of the Projects City.
Assembly of Half-Bridge (2 Lane) at site
Shifting of First-Half of Central Span by simple pulley system 29.12.2006
26.02.2007 First half portion Shifted and Lowered down to position Second Half ready for shifting
26.02.2007 shifting in progress for Second half (r.h.s.) of Bridge
View from other side - Second half shifted, to be lowered 26.02.2007
COMPLETED BRIDGE Central Portion Full View
THANKS Quarries are welcome --- ---- for sharing knowledge
